docs: def launch_ipython(argv=None, ipython_app=None):
      """
      Launch IPython from this interpreter with custom args if needed.
      Chimera magic commands are also enabled automatically.
      """
      try:
          if ipython_app is None:
              from IPython.terminal.ipapp import TerminalIPythonApp as ipython_app
          from traitlets.config import Config
      except ImportError:
          sys.exit("ERROR: IPython not installed in this environment. "
                   "Try with `conda install ipython`")
      else:
          # launch_new_instance(argv)
          app = ipython_app()
          c = Config()
          code = ["from pychimera import enable_chimera_inline",
                  "enable_chimera_inline()"]
          c.InteractiveShellApp.exec_lines = code
          app.update_config(c)
          app.initialize(argv)
          app.start()